The body of a man who apparently tried to break into an elementary school was discovered Friday in an air conditioning duct on the roof of the cafeteria, police said.

The man, whose identity hadn't been released as of Friday afternoon, tried to use the duct to get into Sierra Vista Elementary School and died there, said Sgt. Andy Hill, a Phoenix police spokesman.

Police didn't know why the man tried to break in or how long he had been there. "Obviously because of the smell, there are indications that he had been there for some time," said Hill.

The cause of death wasn't known but Hill said it wasn't considered a homicide. Police didn't release any details about the man.

The body was found as a plumber investigated a foul odor, said Superintendent Mark Dowling of the Roosevelt School District.

Dowling said cafeteria staff noticed the odor early in the day and called in school maintenance staff, who then called a plumber because they thought the odor might be related to the plumbing.

Parents were notified immediately through an emergency phone system that called students' homes and played a recorded message, said district spokeswoman Lori Rieger.

School officials said the children are dismissed early on Fridays and that some parents were already on their way when the school notified parents.

Rieger said the school was locked down after the discovery and that some students left early with relatives but that there was never an evacuation. She said students who weren't picked up early stayed in class through the day and ate lunch in the library. The cafeteria was never used Friday.

The school has about 550 students in preschool through eighth grade.

David Torres, who arrived at the school at midday to pick up his two sons, said he was surprised to see police and TV helicopters when he arrived.

"I was thinking something real bad had happened," said Torres, who was leaving with his boys. "I got nervous and I started to look for my kids."

Elisea Limones said she was shopping across the street from the school, where two of her nephews are students, when she saw the commotion.

"I was scared, I was frightened, of course," she said. "I didn't know if any of the kids were harmed."

Limones picked up her nephews — a third-grader and sixth-grader.

Dowling said a psychologist will be at the school when it reopens Tuesday.